[Perf] Linux/x64: 1 Regression on 7/13/2026 8:32:42 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [a90733cc40d6c7037a37d9c2b5c2403b8cac490f](https://github.com/dotnet/runtime/commit/a90733cc40d6c7037a37d9c2b5c2403b8cac490f)
Compare | [f2b30309fd488f1c3fd41c18723a7c80a81f4c67](https://github.com/dotnet/runtime/commit/f2b30309fd488f1c3fd41c18723a7c80a81f4c67)
Diff | [Diff](https://github.com/dotnet/runtime/compare/a90733cc40d6c7037a37d9c2b5c2403b8cac490f...f2b30309fd488f1c3fd41c18723a7c80a81f4c67)
Configs | CompilationMode:wasm, RunKind:micro

### Regressions in System.Tests.Perf_Int128

Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio
-- | -- | -- | -- | -- | -- | -- | -- | --
|

• [CopySign - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

![graph]()
[Test Report]()

### Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

```cmd
git clone https://github.com/dotnet/performance.git
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Tests.Perf_Int128*'
```

### System.Tests.Perf_Int128.CopySign(value: 1, sign: -1)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

[Profiling workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/profiling-workflow-dotnet-runtime.md)
[Benchmarking workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/benchmarking-workflow-dotnet-runtime.md)

Start with src/benchmarks/micro/libraries/System.Runtime/Perf.Int128.cs and the System.Tests.Perf_Int128.CopySign benchmark, then run performance/scripts/benchmarks_ci.py with the provided filter. Compare the baseline and test results using the linked report and profiling workflow. Done means the 1.92x regression is explained and a rerun confirms its resolution or behavior.

Written by the indexing model from the issue text.